1. Field of the Invention
This invention relates to the electronic generation of periodic waveforms. More specifically, this invention relates to techniques for synthesizing one or more phase-locked output signals in response to an input signal.
While the present invention is described herein with reference to a particular embodiment, it is understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional embodiments within the scope thereof.
2. Description of the Related Art
In many digital systems a master clock is used to synchronize the operation of the constituent devices within a system. The individual system components may be driven by a clock waveform or multiple thereof or may operate in accordance with control signal information derived therefrom.
Unfortunately, perturbations in the power supplied to a digital system can cause variation in the frequency of the system clock. Such power supply variation can arise, for example, in systems having a plurality of devices in electrical communication with a single power supply. In particular, such "switching noise" created by variation in the power consumed by one of the commonly-energized devices may alter the power delivered to the system clock.
Operation of the system clock may also be adversely affected by undesired extrinsic noise such as voltage spikes and the like inherently present in the energy provided by the power supply itself. This type of noise irregularity may also give rise to timing errors by creating a variation in clock frequency.
Accordingly, a need in the art exists for a multiple-phase clock generator/multiplier substantially immune from internal power supply noise and from the switching noise associated with system components coupled to a common energy source.